L. Agassiz on the Echinodermata. 303 



G. vulgaris, Lam. — G.abbreviata, Lam. — G.subrotunda, Mant. — (G.qua- 

 drifasciata, Burg., and sexfasciata, Defr., are monstrosities.) 



4. Discoidea, Kl.and Gr. (Conulus, Leske. — Echinodis cites, V.Ph. 

 — Galerites, Lam.) — Differs from the Galerites by the large ambu- 

 lacra pierced with small pores at very short distances from one an- 

 other. All the species are fossil, from the jura and chalk. 



D. depressa, Ag. (Galer. depr., Lam.) — D. speciosa, Ag. (Gal. spec., 

 Mwist.) — D. albo-galera, Ag. (Conulus albo-gal., Leske.) — D. canaliculata, 

 Ag. (Gal. canal., Gold/.) — D. rotula, Ag. (Gal. rot., Al. Br.) — D. rotula- 

 ris, Kl. (Gal. rotul., Lam.)—D. macropyga, Ag. 



5. Clypeus, Kl. (Echinoclypeus, De Bl. — Echinosimus, V. Ph. — 

 Galerites, Lam. — Nucleolites, De Fr.) — Disc circular, more or less 

 flattened ; ambulacra converging towards the apex and towards the 

 periphery of the disc ; anus superior and marginal. All the species 

 are fossil, from the jura, chalk, and tertiary deposits. 



CI. sinuatus, Park. — CI. emarginatus, Phil. — CI. patella, Ag. (Gal. pat., 

 Lam.) — CI. orbicularis, Phil. — CI. Soiverbii, Ag. (Nucleolites Sow., Defr.) 

 — CI. conoideus, Ag. (Echinoclyp. conoid., Leske.) — CI. hemisphcericus, Ag. 

 (Echinoclyp.hemisph.,Z>s#e.) — CI. testudinarius, Ag. (Nucl. testud., Munst.) 

 — CI. scutella, Ag. (Nucl. scut., Gold/.) 



6. Nucleolites, Lam. (Echinobrissus, Breyn. — Clypeus, Phil.) — 

 Disc oval or heart-shaped ; ambulacra more prominent at the apex 

 than at the periphery; they however do not form a petaloid star, as 

 in the genus Clypeus. All are fossils from the jura, chalk, or ter- 

 tiary deposits. 



N. scutata, Lam. — N. clunicularis, Ag. (Clyp. clunic, Smith.) — N. dimi- 

 diata, Ag. (Clyp. dimid., Phil.) — N. planata, Rcem. — N. cordata, Goldf. — 

 N. lacunosa, Goldf. — N. scorbiculata, Goldf, — N. Olfersii, Ag. — N. grigno- 

 nensis, Defr. 



7. Cassidulus, Lam. (Nucleolites, auct.) — Disc oval; ambulacra 

 petaloid, anus between the summit and posterior margin. All are 

 fossils from the chalk and tertiary deposits. 



C. Lapis cancri, Lam. — C. patellaris, Ag. (Nucl. patell., Goldf.) — C. com- 

 planatus, Lam. 



8. FiBULAFviA,Lam. — (Echinocyamus, Leske and Gr.^ — Echinoneus, 

 Goldf.) — Shell spheroidal ; circumference oval or subcircular ; am- 

 bulacra petaloid; anus between the posterior margin and the mouth.. 

 The species are fossils of the chalk and tertiary deposits, and some 

 recent. 



F. placenta, Ag. (Echinon. plac, Goldf.) — F. subglobosa, Ag. (Echinon. 

 subgl., Goldf.) — F. ovata, Ag. (Echinon. ovat., Munst.) — F. scutata, Ag. 



